This invention relates generally to cutting, and more particularly to an apparatus and method for cutting multiple stacks of a desired length from a moving stack of sheet material using high pressure fluid jet streams.
Single blade oscillating or radial saw blades are typically used to cut stacks of flat sheet material into stacks sized for consumer uses. Systems which employ saw blades, while effective for certain uses, suffer from several disadvantages. First, saw blades become dull through the cutting process, and must be continually sharpened, especially when the blades are used to cut extremely tough or durable material such as paper or nonwoven material. Therefore, saw cutting systems often include a timed grindstone which sharpens the blade while in operation. After every sharpening, a residue of abrasive materials, such as carbon particles, is present on the blade. This residue, along with grinding dust, is transferred to the stacks or sheets produced immediately after sharpening. These stacks, therefore, cannot be sold to consumers and must be deposited in a landfill, causing a significant amount of waste. Furthermore, when the paper or nonwoven material being cut is moisture impregnated, centrifugal force from the spinning saw causes liquid to be splattered in a 360 degree circle inside the saw enclosure. The liquid material accumulating inside the saw enclosure is a prime breeding ground for fungus, mold, and germs. The liquid also frequently combines with loose fibers, grinding dust, and other materials, and eventually drops from the saw enclosure onto the products moving through the saw system. These products, therefore, cannot be sold to consumers.
Fluid jet cutting systems are also known in the art. Fluid jet cutting systems have generally been used for cutting stationary sheet material. These systems typically employ a single nozzle. The nozzle may move above stationary material, or material may move beneath a stationary nozzle. In some cases multiple nozzles have been employed to cut multiple sheets from a single stationary sheet. Some systems employ computer control to produce multiple cut patterns in the stationary sheet.
Fluid jet cutting systems have also been used for cutting a continuously moving single web of material. These systems typically employ a single nozzle which makes a single predefined cut in a sheet of material. Therefore, multiple systems are required to make simultaneous multiple cuts in a web of material. In addition, the cut is typically a fixed length or pattern, and therefore can be used only to cut one specific length or shape. Therefore, if it is desirable to supply a variety of products in different shapes and sizes, a different system must be provided for each required cut. Each system requires a significant capital expenditure. Therefore, existing fluid jet cutting systems for cutting a continuously moving web of material are typically very expensive and relatively inefficient.
It is therefore an object of the present invention to provide an improved apparatus and method for simultaneously cutting a plurality of stacks or sheets of a desired length from a moving web of material.
It is another object of the invention to provide a novel method and apparatus for cutting a continuously moving web of material which produce a minimal amount of waste.
It is yet another object of the invention to provide an improved method and apparatus for cutting a continuously moving web of material which require minimal maintenance.
It is still another object of the invention to provide a novel method and apparatus for cutting a continuously moving web of material with minimal down time.
It is a still further object of the invention to provide an improved method and apparatus for cutting a continuously moving web of stacked paper or nonwoven material quickly and cleanly.
It is a still further object of the invention to provide a novel method and apparatus for cutting a continuously moving web of material which provides a variety of different cut sizes.
It is yet another object of the invention to provide a cutting apparatus which is programmable and provides different cut lengths.